Q. 75.0( 1 Vote )
Trace the events
Sneezing is a reflex action that does not require conscious direction or control.
The entire process of response to a peripheral nervous stimulation that occurs involuntarily is called a reflex action. It is defined as an inborn, involuntary mechanical response to stimuli. The reflex pathway comprises at least one afferent neuron and one efferent neuron appropriately arranged in a series. The afferent neuron receives signal from a sensory organ and transmits the impulse via a dorsal nerve root into the CNS. The efferent neuron then carries signals from CNS to the effector.
The sequences of events occurring during sneezing are:
• Nerve endings located in the nasal passage identifies the irritant entered in the nose.
• Receptor sends the information or nerve impulse to the sneezing centre located in the brain stem.
• Brain stem sends instructions to the lungs or diaphragm for response.
• Diaphragm moves abruptly and the chest muscles contract in response to the instructions received.
• Air blows out from nose and mouth rapidly.
• Sneezing occurs in response to the irritant.
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